1. Field of the Invention
The present invention relates generally to radiator assemblies for use in motor vehicle cooling systems and, more particularly, to a thermal expansion joint provided in a side sheet of a radiator and a method for making the same.
2. Description of the Related Art
Motor vehicles utilize a radiator assembly to eliminate waste heat from the internal combustion engine of the vehicle. The waste heat is a by-product of the internal combustion process and must be removed to allow steady state operation of the vehicle powertrain system. The radiator assembly generally includes a frame mounted to the chassis of the motor vehicle and a radiator mounted to the frame, the radiator comprising a core, or heat exchanger, and inlet and outlet manifolds or header tanks which communicate with the core. The radiator core comprises a plurality of tubes and fins, typically disposed in alternating laterally extending rows, with the tubes communicating with the inlet and outlet tanks so as to provide a flowpath for an engine coolant fluid, particularly water or glycol. At each side of the radiator core, a side sheet is brazed to the fins and extends between the header tanks. Ambient cooling air is forced across the tubes and fins during operation of the vehicle, resulting in heat transfer from the heated engine coolant flowing inside the core tubes to the ambient air stream.
U.S. Pat. No. 5,570,738 to Christensen discloses an exemplary radiator assembly for use in a motor vehicle, the disclosure of which is incorporated herein by this reference. The radiator assembly disclosed in Christensen includes a spring member coupled to one end of the radiator and to the frame for accommodating lateral thermal growth of the radiator relative to the frame.
In addition to the thermal growth of the radiator relative to the frame, the radiator itself experiences thermal growth during operation. Specifically, the radiator core tends to expand as its operating temperature increases. As a result, stress is created at the attachment between the core and the side sheets.
Consequently, a need exists for an improved radiator side sheet that provides the necessary thermal relief as the radiator core expands during operation.